The birth of diamonds is governed by geology nanodiamonds appear at low pressure and temperature

Geology drives the birth of new nanodiamonds

Natural diamonds have the peculiarity of being formed as a result of geological processes at low pressure and low temperatures. This mechanism is far from the classical concept of the ultra-high pressure diamond formation process. However, a new research confirms that there is another way of birth of diamonds controlled by geology. The study was carried out by the specialists from the University of Earth Sciences of Barcelona.

Diamond is recognized as the densest material on our planet. It is considered as a symbol of wealth and luxury. It is a gem and the most durable mineral that is formed by chemically pure carbon.

According to a scientific hypothesis, it crystallizes a cubic system under conditions of ultra-high pressure at great depths of the Earth's mantle. For the first time, the researchers were able to confirm the formation of natural diamond at low pressure. The process was observed in the oceanic rocks of the Moa-Baracoa ophiolite massif in Cuba. The geological structure is located on the northeastern side of the island and is formed by ophiolites, which are typical rocks of the oceanic lithosphere.

These rocks are found on the continental margin of North America. They could have formed during the collision of the arch of the Caribbean Ocean, the event occurred 70-40 million years ago. The beginning of formation could have been recorded on the seabed approximately 120 million years ago.

Oceanic rocks have undergone various changes due to the infiltration of sea water. The result was in small fluid inclusions within the olivine. According to the mineralogy professor Joaquin Proenz, the liquid inclusions contain nanodiamonds. Their size can reach from 200 to 300 nanometers.

In addition, the composition includes serpentine, magnetite, silicon and pure methane. And they were all formed at low pressure in the process of changing olivine.

The scientists believe that in this way they were able to describe for the first time the process of ophiolite diamond, which was formed at low pressure and at low temperature in natural conditions.

Reference: “Diamond forms during low pressure serpentinisation of oceanic lithosphere” by N. Pujol-Solà, A. Garcia-Casco , J.A. Proenza, J.M. González-Jiménez, A. del Campo, V. Colás, À. Canals, A. Sánchez-Navas, J. Roqué-Rosell, 10 September 2020, Geochemical Perspectives Letters. DOI: 10.7185/geochemlet.2029